If you bought Snapselect on the App Store after reading the initial and followup Quick Looks, be advised that V1.1 is out. Your Mac may not be set to auto update and if not, you definitely want this update in your machine. As they promised, the folks at Macphun have improved the user interface, particularly to help serious photographers and editors who want to use Snapselect in conjunction with Lightroom or Aperture. If you have not bought it yet, today might be the day. Do note that like all Macphun software, it is Mac only. I ran into some snags getting it to see images inside folders inside my existing Lightroom catalog, but getting to images in folders or on a card was no problem at all. I was able to read folders from my Lightroom catalog with a different set of images. So the issue could have been something to do with the first set being images from a Canon EOS-M. You can also browse by Collection, a tool that I use all the time, but be aware that with this release Snapselect can only deal with top level collections, not collections stored inside Collection Sets. While I find this inconvenient, I think it is fair to recall that Snapselect is designed to cull before you go through the whole import and collection building process.
I am not sure which RAW converter Snapselect is using, I suspect it may be the OS X native one. What I found interesting is that Snapselect was able to open folders and browse images including EXIF and histogram for Hasselblad's proprietary 3FR RAW format. Photo Mechanic cannot do that and neither can the DXO tools.
Loading of an example folder of 500+ images took just over one minute, including the analysis phase. The "similar" function is very effective. I used a folder from a recent hockey game shoot and was very impressed by how the software gathered like images together as there were numerous burst mode sets of breakaways or glove saves. The timeline view shows the images as they were captured, but as I noted in the third 7D Mk II review, the save sequence with the SD card looks like last frame in the burst first, instead of first to last.
It's also handy to be able to group shots into time intervals. I used the default example of 5 minute blocks and it really simplifies the edit process. You only need to know two keys Z is a pick, X is a reject. This is very quick but inconsistent with the Lightroom Pick/Reject keyset. I don't see these as reassignable at this point.
While there are other options such as a the much richer and much more expensive Photo Mechanic, Snapselect could very well be the culling program for the majority. It is fast, easy to use and benefits from the talents of the Macphun developers. If you shoot more than 100 images in a session, you need a culling tool and at $25, this is perfect, but buy it while it is on sale for $14.99 and you really cannot lose.